1. Field of the Invention
The present invention relates to a turnstile with automatically pivoting arms. More particularly, it relates to a turnstile where the arms are automatically lowered upon power loss and automatically reset upon power restoration.
2. The Prior Art
Turnstiles are used as gateways in order to control the access or exit of pedestrians. The passage through such gateways is controlled by moving the turnstile through steps depending on previously defined criteria, which can be automatically checked. At the same time, uncontrolled and quick passage through such gateways for pedestrians must be assured in selected situations, such as, emergency situations.
Such a turnstile installation is known, for example, from DE-OS 2,825,787. In the event of power failure or if the power is switched-off, an electromagnet is de-activated and a releasing device is no longer maintained in a pre-cocked position. The releasing device slides under spring force to pivot a locking bar supporting the locking arm which becomes disengaged from a bearing tongue connected with the locking arm. Thereafter, the force of gravity acting on the locking arm causes the latter to drop into a folded-down position clearing the passage. To reset the turnstile, the locking arm has to be pivoted by hand into the horizontal position until the bearing tongue is locked again with the locking bar. In addition, the slide has to be moved again into its original operating position by the electromagnet of the releasing device against the spring force acting on the slide.
The prior art turnstile has to be equipped with a powerful electromagnet. Resetting the turnstile by hand following a power loss is quite complicated, especially when large numbers of turnstiles are involved.